1. Field of the Invention
The present invention relates to improvements in an air cleaning system for cleaning the polluted air in a vehicle passenger compartment.
2. Description of the Prior Art
It is well known that various kinds of air cleaning systems have been proposed and used practically for cleaning air in a vehicle passenger compartment. A typical air cleaning system includes an air cleaner unit which is disposed on a rear parcel shelf in the vehicle passenger compartment. The air cleaner unit is provided with a fan unit, and an air filter unit made of a dust filter and a deodorizing filter. The air cleaner unit is designed to suck air from the vehicle passenger compartment therein by means of the fan unit and to deliver the air to the vehicle passenger compartment after cleaning the air by the air filter unit.
However, due to the limitation of size and cleaning capacity of the air cleaner unit, it takes a relatively long time for such an air cleaning system to accomplish the cleaning operation when the air in the vehicle passenger compartment contains a large quantity of impurities such as tobacco smoke. Furthermore, if the driver wishes to obtain fresh air from the outside of the vehicle such an air cleaning unit can cause a problem in that, if the street is busy, exhaust gasses are sucked in the passenger compartment and the air in the compartment is rapidly polluted.